<form action="{% url 'blog:search' %}" method="get">
    {% csrf_token %}
    <div class="field has-addons">
        <div class="control is-expanded">
            <input type="search" class="input" name="keyword" placeholder="Search" value="{{ keyword }}">
        </div>
        <div class="control">
          <input  class="button is-primary" type="submit" value="搜索">
        </div>
      </div>
</form>